Abstract:
Brick masonry structures are the most common type of structures built in Bangladesh.
Significant increase in load carrying capacity of brick masonry columns is possible
through encasement by ferrocement overlay. This study investigates the possibility of
using precast ferrocement jackets for brick masonry columns. A total of thirty-two
brick masonry columns and two hollow ferrocement columns were constructed and
tested in this investigation. The brick columns were divided into four sets. The first
set of columns were completely bare, the second set of columns were with plaster, the
third set of columns had precast ferrocement jackets divided into two equal halves,
around the columns and the fourth set of columns had precast ferrocement jackets
divided into three segments, around the columns. The brick columns in a set were
made with mortar having different cement-sand ratio and water-cement ratio. The
cement-sand ratio of mortar used for plastering and construction of precast
ferrocement jacket was 1:2. The thickness of plaster and precast ferrocement jacket
was 15mm. The columns were fabricated in the laboratory, cured for 21 days and
tested at 28 days using Universal Testing Machine.
All the columns were tested under increasing load until failure. From the test results it
was observed that the cracking and failure stresses of columns with precast
ferrocement jackets were substantially higher than those of the bare brick masonry
columns and columns with plaster. It was also observed that the application of rich
mortar plaster over bare brick masonry columns does not increase the cracking stress
and failure stress significantly. The cracking and failure stresses of columns with
precast ferrocement jackets divided into two halves were nominally higher than those
of the columns with precast ferrocement jackets divided into three segments. The
failure of bare brick masonry columns and column coated with plaster is sudden and
crack width increases rapidly after their formation, leading to a brittle failure for the
system. On the contrary the failure of column with precast ferrocement jackets
occurred slowly, exhibiting much ductile response at failure.
